Wheel-guard.



J. N. HEALD &- A. M. DRAKE.

WHEEL GUARD.

APPLICATION FILED SEPT- 6. 19:1.

, Patented Dec. 18, 1917.

2 SHEETS-SHEET l- J. N. HEALD & A..M. DRAKE.

WHEEL GUARD.

APPLICATION FILED SEPT- 6. 9H-

1,250,168-. Patented m0. 18,1917.

2 SHEETS-SHEET 2- barren snares rarnnr ornrca.

JAMES N. HEALD AND ALDEN M. DRAKE, OF WORCESTER, MASSACHUSETTS,ASSIGNORS TO HEALD MACHINE COMPANY, OF WORCESTER, MASSACHUSETTS, ACORPORATION OF MASSACHUSETTS.

WHEEL-GUARD.

Patented Dec. 18, 191 7.

Application filed September 6, 1917. Serial No. 189,905.

To all whom itmay concern:

have invented a new and useful WVheeL Guard, of which the following is aspecifi- ,cation.

This invention relates to a wheel guard, particularly designed for useon grinding "machines though capable of more general .jtive position. 0

"'ments and combinations of parts which will ap lication.

11 certain types of grinding machines, and particularly in internalgrinding machines, it is impossible to use a wheel guard which is fixedin relation to the grinding wheel, be-

- cause of the necessary forward movement of the wheel inside of thework. It has been found, however, that accidents sometimes occur on suchmachines, particularly during the operation of gaging or testing thesize of the hole last ground, after the wheel has been withdrawntherefrom.

Such accidents are caused by the sticking of the gage in the hole,followed by its abrupt release when special force is applied thereto.

The hand or arm of the operator is thus forced backward against therapidly revolving Wheel.

It is the object of our invention to provide a wheel guard which isnormally in inoperative position, but which will be moved to operativeposition upon thewithdrawal of the wheel from the work. We have shownour invention as embodied in an internal grinding machine in which thework head and the wheel head are relatively movable to advance andwithdraw the wheel from the work. An important feature of our inventionrelates to the provision. of suitable connections by which the guard isadvanced to operative position to cover the wheel upon a relativemovement of separation of the wheel and work heads. We have alsoprovided means for normally retaining the wheel guard ,in inoperativeposition, and means permitting a further movement of separation of theheads after the guard is in opera- Our invention further relates toarrangebe hereinafter described and more particularly pointed out in theappended claims.

A preferred form of our invention is shown in the drawings, in whichFigure 1 is a plan view of an internal grinding machine embodying ourinvention;

Fig. 2 is a similar plan View, with the parts in grinding position;

Fig. 3 is a'front elevation of the machine;

Fig. 4 is a detail plan view of the wheel guard;

Fig. 5 is a sectional elevation on the line 55 of Fig. 4, and

Fig. 6 is a plan view of a chain-holding plate.

Referring to the drawings, we have shown our invention embodied in aninternal grinding machine of a common type, having a frame 10, a fixedWork-supporting head 11, a movable wheel head 12, and an internalgrinding wheel W. The wheel head 12 is mounted on a cross-slide 13movable transversely upon a table or base slide 14 which in turn ismovable longitudinally on the frame 10 of the machine.

My improved wheel guard comprises a guard or plate 20 angularly andlongitudinally adjustable upon a rod 21 which in turn is both angularlyand longitudinally adjustable in the arm 22 of a bell-crank which ispivoted upon a stud 23'fixed in the cross- The second arm 28 of thebell-crankiij oonl nected by a spring 29and a chaini 3Q} slotted plate31 (Figs. 1 and 6) fixed to i work head 11. The spring 26'i'ssd'dispo'sfe'd that it normally moves the arm 22 and 2O to'inoperativeposition. When, howevenf the wheel" head iswithdrawn or separated fromthe work head, the chain 30 and spring 29 will be tensioned .until theguard 20 is thrown into position in front of the grinding ,wheel, whichis thereby protected so as to prevent accidental contact therewith. .11the movement of separation is more than sufficient to bring the wheelguard to operative position, the spring 29 will stretch to permit of theadditional movement.

We have thus provided an extremely sim ple wheel guard which isautomatically advanced to operative position whenever the wheel is movedto a position in which it may be dangerous to the operator. As the wheelis again advanced toward the work, the

spring 26 is permitted to operate to remove the guard from operativeposition. I

Having thus described our invention, it

7 Will be evident that changes and modifications can be made therein bythose skilled in the art without departing from the spirit and scope ofour invention as set forth in the claims, and we do not wish to beotherwise limited to the details herein disclosed, but

'- I I what we claim is 1, In a grinding machine, in combination,relatively movable wheel and work heads, a wheel guard, means to holdsaid guard normally in inoperative position, and means to move saidguardto operative position upon relative separation of said heads.

2. In a grinding machine, in combination, a grinding wheel, relativelyseparable wheel and work supports, a normally inoperative wheel guardmounted on the wheel support, 7

and means efl'ective to move said guard to operative; position as thewheel and work 7 heads 5. In a grinding machine, a wheel head, a wheelrotatably mounted thereon, a guard, aspring normally holding said guardin inoperative position, and means to advance to said guard to operativeposition as the wheel is withdrawn from the work.

6. lln a grinding machine, a grinding wheel, a wheel head, a guardmounted on said head movable horizontally to operative and inoperativepositions, a spring efi'ective' to swing said guard normally toinoperative position, a member movable relatively to said wheel head asthe wheel and work are separated, and a connection from said mem- 60 Iher to said guard, eflective to move said guard to operative position onsuch relative separation of wheel and Work.

7. In a grinding machine, a grinding wheel, a wheel head, a guardmounted on as said head movable horizontally to operative andinoperative positions, a spring efl'ective to swing said guard normallyto inoperative position, a member movable relatively to said wheel headas the wheel is being with drawn from the work, a connection from saidmember to said guard, efiective to move said guard 'to operativeposition, on such relative movement of said wheel and member, and meanspermitting further relative 73$ movement of said member after said guardis operatively positioned.

8. ln a grinding machine, a grinding wheel, a wheel head, a guardmounted on.

said head movable horizontally to operative and inoperative positions, aspring efiective to swing said guard normally to inoperative position, aconnection to said guard efiective to move said guard to operativeposition on relative separation of the wheel and work,

and a spring in said connection adaptedto yield upon further separationof said parts after said guard is operatively positioned.

In testimony whereof we have hereunto affixed our signatures I JAMES N.HEALD. "ALDEN M. DRAKE.

